Basketball is one of the sports which utilizes a seamed game ball made from leather, rubber or various polYmeric materials.
Early manufacturing processes utilized strips of leather which were sewn together and secured to a bladder. This stitching created a rough raised or indented seam between the strips.
As rubber and other polymerics supplemented leather, manufacturing processes evolved which could eliminate seams. Seams, however, had become necessary and relied upon by athletes for gripping and controlling the game ball.
In baseball, for example, the raised seams allow the pitcher to grasp the ball and by varying his grip throw a fastball, curve, or many other pitches.
In basketball, the channel seams serve several purposes to the athlete leading the athlete to position his fingers in contact with a seam or seams whenever possible. When the athlete bounces the ball, the seams afford the athlete control over the ball's rotation, direction and other handling characteristics. When the athlete holds the ball, the seams provide a surer grip; when he passes the ball, the seams provide more accurate control over the ball's release and direction. When the athlete shoots at the basket he uses the seams to control the release point, rotation, velocity and trajectory of the ball. The seams also provide feedback to the player about the alignment of the shot through the uniformacy of the rotation of its seams.
There are a number of inventions which actually utilize the seams for a variety of purposes, both instructive and utilitarian.
U.S. Pat. No. 3,858,876, teaches the providing of gripping indicia on the surface of the ball to aid the athlete in locating his hands and fingers in essentially the same manner each time before shooting the basketball.
U.S. Pat. No. 4,345,759, discloses a single circumferential 360.degree. line around the periphery on the center of the ball. The athlete can focus on the line throughout the entire shot and observe what corrections are necessary on subsequent shots. Accordingly, the seams are very important to the athlete in affording the athlete maximum control in making his shot and to provide feedback to the athlete for adjustment to increase the effectiveness of the control he imparts to the ball.